you have to change the color of text or background
to change this you have to write css to your blocked css or to change the color of text you have to change color of view.php in your block where the results show

Yes, i have tried to edit the view.css in ROOT/concrete/blocks/survey with no results.
The theme (Hi-Vis) is purchased from the marketplace, and I've already reported an issue about it. (I wonder why the C5 team approves themes without proper testing?)

There was an old discussion about the issue:
http://www.concrete5.org/community/forums/customizing_c5/core-surve...
and i added the code suggested (best answer) to view.php in the location above, but it seems that this is already fixed in the C5 core but doesn't apply?

Try from the old discussions....as described
try

Hope this helps